As electronic products move to smaller size, higher density and performance, semiconductors have correspondingly become smaller with their components and connections becoming denser. This in turn has lead to the development of multichip packages (MCPs) in which a plurality of semiconductor chips are stacked on a substrate such as a printed circuit board. This creates a high density, high performance package that is nonetheless small in size.
In current ball-grid-array (BGA) type of MCPs, the same functional chip terminals (i.e. chip I/Os) of the semiconductor chips in an MCP are often connected together. The commonly connected chip terminals are connected to the same external terminal, such as a package terminal. However, good chips may be wasted in an MCP when one chip of the MCP is defective; even though other chips may be otherwise operable, the entire MCP may be unusable due to the one defective chip.
Therefore, it is desired to provide new electrical connections in MCPs.